Isaac Newton

Isaac Newton was an English physicist and mathematician, one of the most influential scientists in history. He formulated the laws of motion and of universal gravitation, and he developed the calculus, and his work provided the foundation for classical mechanics.

Life

Newton was born in 1642 in Woolsthorpe, Lincolnshire. He studied at Trinity College, Cambridge, and became a fellow of the college and later a professor of mathematics.

He served as president of the Royal Society and as Master of the Mint. He was knighted in 1705 and died in 1727. He was buried in Westminster Abbey.

Mathematics

Newton developed the calculus, independently of Gottfried Leibniz, and he made fundamental contributions to algebra and to the theory of series. The calculus provided the mathematical tools for the analysis of motion and of change.

The dispute with Leibniz over the invention of the calculus was long and bitter, and it divided mathematics for a generation. The notation of Leibniz ultimately became standard, though the concepts were developed by both.

Mechanics

The Principia Mathematica, published in 1687, set out the laws of motion and the law of universal gravitation. The three laws of motion describe the relation between force and motion, and the law of gravitation describes the attraction between masses.

The work unified terrestrial and celestial mechanics, showing that the same laws govern the fall of an apple and the orbit of the moon. It provided the framework for physics for more than two centuries.

Optics

Newton's work on optics included the demonstration that white light is composed of a spectrum of colours, and he constructed a reflecting telescope to avoid the chromatic aberration of refracting telescopes.

His theory that light consists of particles was challenged by the wave theory of Christiaan Huygens, and the debate continued until the development of quantum mechanics. His book Opticks was influential in the development of the study of light.

Legacy

Newton's work transformed the understanding of the physical world and provided the model for scientific inquiry. His laws of motion and of gravitation were superseded by the theory of relativity for extreme conditions, but they remain the basis of classical mechanics.

His influence extends beyond physics to mathematics, to astronomy, and to the philosophy of science. He is regarded as one of the greatest scientists of all time.

The Principia

The Principia Mathematica, published in 1687, is one of the most important books in the history of science. It set out the laws of motion and the law of universal gravitation, and it demonstrated that the same laws govern terrestrial and celestial motion.

The work is written in the geometric style of the ancient mathematicians, and it is difficult for modern readers. It established the framework for physics for more than two centuries.

The three laws of motion state that a body remains at rest or in uniform motion unless acted upon by a force, that force equals mass times acceleration, and that for every action there is an equal and opposite reaction. The law of gravitation states that every mass attracts every other mass with a force proportional to the product of the masses and inversely proportional to the square of the distance.

The Calculus Controversy

Newton developed the calculus in the 1660s, and Leibniz developed it independently in the 1670s. The dispute over priority was long and bitter, and it divided the mathematical community.

The notation of Leibniz, which is more convenient for calculation, became standard, while the concepts were developed by both. The dispute delayed the exchange of ideas and harmed the development of mathematics in Britain.

Alchemy and Theology

Newton spent much of his time on alchemy and on theology, subjects that were not published in his lifetime. He wrote extensively on the interpretation of the Bible and on the nature of the Trinity, and he held views that were unorthodox.

His alchemical work was motivated by a search for the principles of matter and of transformation. Though it did not lead to the results he sought, it reflects the breadth of his interests and the context of his science.

Optics and the Nature of Light

Newton's Opticks, published in 1704, presented his experiments on the refraction and the dispersion of light. He showed that white light is composed of a spectrum of colours, and he argued that light consists of particles.

His theory was challenged by the wave theory of Huygens, and the debate continued until the development of quantum mechanics, which combines aspects of both. His work on optics influenced the development of the study of light and of colour.

Summary

Newton transformed the understanding of the physical world and provided the model for scientific inquiry. His laws of motion and of gravitation, his work on optics, and his development of the calculus made him one of the greatest scientists of all time.

See also

• Albert Einstein
• Galileo Galilei
• Classical mechanics